Polarization and distance dependent coupling in linear chains of gold nanoparticles
We studied collective surface plasmon excitations in chains of gold nanoparticles. The resonance frequency of these excitations is a function of the distance between the particles and polarization of the incident light. The near-field coupling between the particles in a chain leads to a cosine squared angular dependence between the polarization of the incident light and the axis connecting the particles. The far-field coupling between the particles results in a sine squared angular dependence. When the incident light is polarized along the chain, the near-field coupling exhibits a red shift, while the far-field exhibits a blue shift of the collectivemore »